When fastening a sensor, such as, for example, a sensor for an airbag, it is required that the fastener means, that is, one or a plurality of threaded fasteners must not project beyond the sensor, otherwise the danger is to be seen that the safety belt which is attached to a column of the car body contacts the end of a solid fastener and thus may be damaged. A fastening of such a housing from the opposite side normally is not possible as the hollow column does not admit access to the interior thereof.